The Muslim News has an interesting article in it's archives by Jahan Mohmood, an expert on South Asian communities entitled "Stories of Muslim soldiers on the Western Front during WWI" which throws up some amazing statistics highlighting the Muslim presence during the two World Wars:
"When Britain declared war on Germany in 1914, there were only 155,000 personnel in the British Indian Army. By the end of World War I more than 1,300,000 soldiers had volunteered for service. The largest ethnic class to serve Britain were the Punjabi Mussalmans. The majority of these men had come from the cities of Rawalpindi, Jhelum, Attock, Lahore and Rohtak. In addition to the Punjabi contribution there were large numbers of sepoys recruited from the North West Frontier Province. Pashtuns from Peshawar, Kohat, Waziristan and Nowshera had all played a pivotal role in the defence of the British realm.
From 1914 to 1915, 138,000 Indian soldiers were involved on the Western Front; in Europe. With mounting casualties, Indians were despatched to Europe to plug holes in the crumbling Allied line.
By Armistice Day 1918, more than 400,000 Muslims had enlisted, Muslims, Sikhs, Gurkhas and Hindus had all witnessed the horrors of trench warfare on the Western Front as well as the ‘bloody’ campaigns for Mesopotamia and Africa. In total approximately 60,000 men perished, 13,000 medals and 12 Victoria Crosses were awarded to Indians for valour and courage."
You can read the full article here